Thanks — interesting reading.

Distilling the discussion there, below are my takeaways.  Am I interpreting 
correctly?

1) The spillover phenomenon and thus the small number of discrete sizes that 
are effective without being wasteful — are recognized

2) "I don't think we should plan teh block.db size based on the rocksdb 
stairstep pattern. A better solution would be to tweak the rocksdb level sizes 
at mkfs time based on the block.db size!”

3) Neither 1) nor 2) was actually acted upon, so we got arbitrary guidance 
based on a calculation of the number of metadata objects, with no input from or 
action upon how the DB actually behaves?


Am I interpreting correctly?


> Btw, the original discussion leading to the 4% recommendation is here:
> https://github.com/ceph/ceph/pull/23210
> 
> 
> -- 
> Paul Emmerich
> 
> 
>> 30gb already includes WAL, see 
>> http://yourcmc.ru/wiki/Ceph_performance#About_block.db_sizing
>> 
>> 15 августа 2019 г. 1:15:58 GMT+03:00, Anthony D'Atri <a...@dreamsnake.net> 
>> пишет:
>>> 
>>> Good points in both posts, but I think there’s still some unclarity.

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